The field of the invention is nozzles for dispensing chemical concentrates, and particularly a nozzle which can be attached to a spray nozzle and provide a foam.
Foam nozzles that attach to spray nozzles are well-known. These are described in U.S. Pat. Nos. 4,603,812; 5,611,490; 5,647,539; and 6,164,565.
U.S. Pat. Nos. 4,603,812; 5,611,490; and 6,164,565 utilize radial passages for introducing air into a foam nozzle. These have drawbacks in that water and foam can be expelled from the radial passages. Further, these nozzles are retained by a detent or locking arrangements which makes them very difficult to remove.
In U.S. Pat. No. 5,417,371, axially positioned air vent channels are employed. However, they do not introduce air upstream of the nozzle body 10.
In U.S. Pat. No. 3,964,689, a nozzle means is disclosed to provide foam from a hose-end dispenser device. While air is introduced upstream of a screen 68, this arrangement is not provided in a foam nozzle that attaches to a spray nozzle. Neither does the foam nozzle prevent leakage.
What is needed is a foam nozzle attachment for a spray nozzle which reduces the incidence of water or foam leaking from it. Also desirable is a foam nozzle attachment which is readily removed from a spray nozzle when it is no longer wished to be used. In addition, it would be advantageous to have a foam nozzle attachment which does not affect the dilution rate of the chemical concentrate being dispensed.